I was hoping someone here can help me with this same problem I am facing. I have tried searching various forums and guides available online to install and configure OpenVPN for a solution, but to no avail. However, I am no expert, and if I have missed something, I sincerely apologise and would only ask you to point me in the right direction.

Situation:
I have a home network with an IPv4 network 192.1.168.1.0/24 and have been provided with a fixed public IP by my ISP. I would like to set up a downloading station with Sonarr, Radarr and Transmission running on an old Dell XPS machine. I would then like to have all of my downloads to pass through a VPN service provider (NordVPN), however, I would still like to maintain remote access to the machine (I should be able to put my public IP/domain name with a port number and should be connected to the server on my internal network). I should add, that I also do have a Synology NAS, where the same setup are presently running, however for quicker response, I would like to use a linux-based server.

I managed to get through to installing and accessing all services from the internet, however, I just can't seem to install OpenVPN. I try to pass the following command with a non-root user with sudo privileges:

sameep@sam-srv:~$ sudo apt install openvpn
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
openvpn : Depends: initscripts (>= 2.88dsf-13.3) but it is not installable
E: Unable to correct problems, you have held broken packages.
sameep@sam-srv:~$

Have I done something wrong? It is a new Ubuntu 18.04 LTS installation and only the above mentioned services have been added to the system.